We had a couple places when updating review request counters where we'd

fetch a values_list of PKs, and then pass that directly into future

queries, which would end up evaluating them as subqueries. This has two

problems--first, we end up running the subqueries multiple times, and

second, it's impossible to use assertQueries.
This change fixes those up. There are still cases where we have

subqueries that are added by Django's QuerySet.update() method, but

this handles the stuff in our own code.

Verified with assertQueries usage that we no longer had subqueries for

these.